I regard written words as keys that unlock concepts in the mind of the reader. Misspelled words are like keys that don't quite fit, but they'll work if you jiggle the lock a bit. This is very distracting as it disrupts the flow of the ideas.
My nephew's school has some program called "Brave Spelling", where apparently they encourage the pupils' best guesses. I don't know any of the particulars; my SiL does not brook any criticism of him, either express or implied, and I don't know if the teachers tell him what the correct spelling is or if he is supposed to magically know better when he goes into the 3rd grade or something. Without reading correct spelling it's pretty hard to recognize a misspelled word when you see it. We don't need to pay big bucks to teach people to spell like Charles Russell.
The one grammar/spelling error that seems to chap my hide the most is the apostrophe gratuitously inserted into ordinary plurals. The Office Manager at one place I worked did that, until I very gently explained (with citation to authority!

) that it was not necessary and was in most cases wrong. Sadly I have a beautiful pen and ink poster by Ivan Jesse Curtis that has memorialized that error. "All of My Hero's are Cowboys."
Edit to add:
I found it!
Eye halve a spelling chequer.
It came with my pea sea.
It plainly Marx four my revue
Miss steaks eye kin knot sea.
Aye strike a key and type a word
And weight fore it two say
Weather eye am wrong oar write
It shows me strait a weigh.
As soon as a mist ache is maid
It nose bee fore two long
And eye can put the error rite
Its rarely ever wrong.
Eye have run this poem threw it -- I am shore your pleased too no
Its letter perfect in it’s weigh
My chequer tolled me sew .
The use of the word "but" usually indicates that everything preceding it in a sentence is a lie.
E.g.:
"I believe in Freedom of Speech, but". . .
"I support the Second Amendment, but". . .
--Randy